1. Field of the Invention
This invention relates to new monoclonal antibodies having a specific binding property to human immunoglobulin E (IgE) and useful for the treatment of allergic diseases.
2. Description of Prior Art
Immune reaction is a defensive mechanism of a living body to protect against the invasion of foreign microorganisms from outside of the body such as an infection. This mechanism may affect the living body and is generally called an allergy. Recently, allergic rhinitis caused by the pollen of Cryptomeria japonica has been the focus of attention. Allergy is classified into types I to IV with its occurring processes. Type I allergy is a typical allergy known as immediate-type allergy and generally called allergy. The type I allergy is mediated by immunoglobulin E (IgE) and the immune response caused by IgE antibody starts by the following mechanisms.
First, IgE binds to Fe.epsilon. receptor on mast cells in tissue or basophils in the blood, then an antigen binds to a recognition site in the antibody to form a cross-linked structure between IgE antibodies. Mast cells and basophils are stimulated by the cross-linkage and release various chemical mediators which cause a variety of allergic attacks such as asthma and edema.
Elucidation of the allergic response mechanism initiated studies to investigate medicines that act to IgE for the prevention and treatment of allergy. Particularly, IgE antibody has been tried for the treatment and prevention. For example, Japanese Un-examined Patent Publication No. 102032 (1989) discloses a treatment by anti-IgE antibody bound to a toxin to selectively attack cells having IgE antibody on their surfaces and eliminate IgE producing cells. On the other hand, it has been pointed that binding of these antibodies to IgE on the surfaces of mast cells and basophils to form cross-linked bridge of IgE antibodies on the cell surfaces causes to stimulate adversely the release of chemical mediators. Application of neutralizing antibody against IgE antibody also shows similar results. Japanese Un-examined Patent Publication Nos. 289100 (1986) and 127977 (1991) disclose the prevention and treatment of allergy by the use of an monoclonal antibody to Fc.epsilon. receptor which specifically binds to IgE to inhibit the binding of IgE antibody to mast cells and basophils. Chang et al. reported a treatment of allergy by inhibiting the binding of IgE antibody to such cells using an antibody to Fc in IgE antibody (T. W. Chang et al., BIO/TECHNOLOGY, vol. 8, 122-126, (1990)).
Hardly any practical treatment of allergic diseases with monoclonal antibody to IgE antibody has been reported.
Japanese Un-examined Patent Publication No. 72500 (1991) discloses a monoclonal antibody which does neither recognize IgE bound to Fc.epsilon. receptor nor stimulate the release of mediators from cells as a new anti-IgE antibody. Inhibition of histamine release from mast cells derived from human peripheral blood by the treatment with the monoclonal antibody after sensitization with IgE has been confirmed.